Circuit board interconnection system, connector assembly, circuit board and method for manufacturing a circuit board

ABSTRACT

A circuit board interconnection system is disclosed according to the embodiments of the present invention. The system includes a first circuit board, a second circuit board, a third circuit board, a first connector and a second connector. The first connector and the second connector are mounted at two sides of the first circuit board respectively so that the second circuit board mounted on the first connector is perpendicular to the third circuit board on the second connector. The first connector and the second connector mounted respectively at two sides of the first circuit board are coupled to each other via an impedance controlled mechanism on the first circuit board. Another circuit board interconnection system, a circuit board, a connector assembly and a method for manufacturing a circuit board are disclosed according to the present invention. The circuit board adopts the impedance controlled mechanism which has a shielding function and an impedance controlled function to replace a via hole on the existing circuit board where the via hole has an uncontrollable resistance.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Application No.PCT/CN 2008/070741, filed on Apr. 17, 2008, which claims the priority ofCN application No. 200710107167.8 filed on Apr. 30, 2007, entitled“CIRCUIT BOARD INTERCONNECTION SYSTEM, CONNECTOR ASSEMBLY, CIRCUIT BOARDAND METHOD FOR MANUFACTURING A CIRCUIT BOARD”, the contents of which areall incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to circuit board interconnectingtechnique, and more specifically, to circuit board interconnectionsystem, connector assembly, circuit board and method for manufacturing acircuit board.

BACKGROUND

Backplane interconnection system is a common circuit boardinterconnection system. The backplane refers to a component whichprovides signal coupling, power supply, guidance, and physical support,etc., for one or more functional circuit boards implementing differentfunctions in a communication system such as a switch, a router, astorage device, a computer or a server. Usually, the backplane includesa multi-layer circuit board, signal/power backplane connector, guidingmechanism, etc.

A backplane interconnection system is formed by mounting one or morefunctional circuit boards implementing various functions on thebackplane connectors of the backplane.

FIG. 1 is a mounting structure of an existing backplane interconnectionsystem. As illustrated in FIG. 1, each functional circuit board 12 isparallel to each other and perpendicular to a backplane 10. Eachfunctional circuit board is inserted into a slot on a backplaneconnector 11 so that the functional circuit board is connected with thebackplane 10. The backplane connectors 11 as illustrated in FIG. 1 areon the same side of the backplane 10. In practice, a plurality ofbackplane connectors 11 may also be located on the two sides of thebackplane 10, i.e., the functional circuit boards 12 can be mounted ontwo sides of the backplane 10.

With the increase of the signal transmission rate, high-speed data buseson the functional circuit boards and the backplane are generallyarranged in a point-to-point differential interconnection topology.However, such topology may produce some undesirable effects on thetransmission performance of each interconnection path in the backplaneinterconnection system. For instance, the high-speed data bus forcoupling each functional circuit board on the backplane may cause signalattenuation on each interconnection path. Moreover, the length of thesehigh-speed data bus may vary with the space among each backplaneconnector, causing different extent of signal attenuation on eachinterconnection path. In addition, FIG. 2 illustrates a schematic of anexisting via hole connection section on the backplane in a backplaneinterconnection system. Multiple via holes 20 connected to the backplaneconnectors are provided on the backplane. Usually, there exists anunwanted portion 21 with a certain length for the via hole 20. Theunwanted portion 21 of the via hole 20 may cause signal reflection.

In addition, the transmission performance of the high-speed backplaneinterconnection paths may be affected by other factors includingmaterial, conductor loss, wiring length, impedance control, delaybetween two transmission cables of a differential pair, and crosstalkbetween the differential pair, etc.

For the above reasons, the insertion loss and the return loss on eachinterconnection path in the backplane interconnection system aredifferent, which increases the difficulty in IC design for the relatedfunctional chips on each functional circuit board. Consequently, thishinders the improvement of the transmission rate and the smooth updateof the backplane.

In order to overcome the foregoing defects, an orthogonal mountingstructure of a backplane interconnection system was proposed. In suchstructure, multiple functional circuit boards are mounted at two sidesof the backplane. Moreover, the functional circuit boards at one side ofthe backplane are in a plane which is orthogonal to the plane that thefunctional circuits at the other side are in. FIG. 3 is a mountingstructure schematic of an existing orthogonal backplane interconnectionsystem. As illustrated in FIG. 3, a front card 301 and a back card 302are respectively inserted into the slots on the two backplane connectorswhich are at two sides of the backplane 300, respectively. The frontcard 301 at one side of the backplane 300 is in a plane which isorthogonal to the plane that the rear card 302 at the other side is in.The backplane connectors at two sides of the backplane are coupledthrough via holes on the backplane 300. Thus, a driver or a receiver(chip) on the front card 301 is interconnected with a receiver or adriver (chip) on the rear card 302.

In such mounting structure, the length of signal cables on the circuitboard which are used to connect slave circuit boards is shortened. Insome case, signal cables can even be eliminated on the backplane. If thepad array in the mounting area for the backplane connector is indiagonal symmetry, that is, the pad array is symmetric along thediagonal of the mounting area for the backplane connector, signal cablescan be eliminated. That is, when the pins are on the front card and rearcard which are orthogonal to each other, corresponding pins of pins mayshare a same via hole.

Referring to FIGS. 4 a˜4 c, FIG. 4 a is a front view of an existingorthogonal backplane interconnection system. FIG. 4 b is a cross-sectionview of the front card 301 shown in FIG. 4 a. FIG. 4 c is a right viewof an existing orthogonal backplane interconnection system. Asillustrated in FIGS. 4 a˜4 c, the signal sent by the driver 311 on thefront card 301 is transmitted along a via hole 312 on the front card,differential signal line 313, a via hole 314 to the backplane connector31 coupled to the front card 301. Then, the signal is furthertransmitted to a receiver 321 on the rear card 302 along the backplaneconnector 21, a via hole 30 on the backplane 300, a backplane connector32 coupled to the rear card 302, a via hole 324 on the rear card,differential signal line 323 and a via hole 322. Each pair of driver andreceiver in the orthogonal backplane interconnection system may realizesignal transmission in accordance with the approaches shown in FIGS. 4a˜4 c.

With regard to the above structure, the existing backplaneinterconnection system still suffers from the below problems. Theinability to control the via impedance may cause severe impedanceinconsistency. Moreover, high signal density may result in aconsiderable crosstalk among via holes, thereby the crosstalk among eachinterconnection path appears.

Therefore, existing circuit board interconnection system like backplaneinterconnection system may suffer from a poor transmission performance.Moreover, the transmission rate is slow and the attempt to improve thetransmission rate may also be hindered.

SUMMARY

In view of this, a circuit board interconnection system, a circuitboard, a connector assembly, an impedance controlled mechanism, acommunication device and a method for manufacturing a circuit board areprovided according to embodiments of the present invention.Consequently, the transmission performance of the circuit boardinterconnection system or the circuit board can be improved.

A circuit board interconnection system is provided according to oneembodiment of the present invention. The system may include a firstcircuit board, a second circuit board, a third circuit board, a firstconnector and a second connector. The first connector and the secondconnector are mounted at two sides of the first circuit board,respectively. The second circuit board is mounted on the firstconnector. The third circuit board is mounted on the second connector.The first connector and the second connector mounted at two sides of thefirst circuit board are connected via an impedance controlled mechanismon the first circuit board.

Another circuit board interconnection system is provided according toone embodiment of the present invention. The system may include a firstcircuit board, a connector mounted on the first circuit board, and asecond circuit board coupled to the first circuit board via theconnector. The first circuit board is provided with an impedancecontrolled mechanism, wherein the impedance controlled mechanism iselectrically coupled to the connector and the second circuit board iselectrically coupled to the first circuit board via the connector andthe impedance controlled mechanism.

A circuit board is provided according to one embodiment of the presentinvention. An impedance controlled mechanism is provided at the positionwhere the connector is mounted on the circuit board.

A connector assembly is provided according to one embodiment of thepresent invention. The connector assembly may include a first connectorand a second connector. The connector assembly includes an impedancecontrolled mechanism. The impedance controlled mechanism includes:

a hollow penetrating pin provided on the first connector, wherein thehollow penetrating pin is in hollow structure made of metal material andthe inner wall of the hollow penetrating pin is covered with adielectric layer;

a penetrating pin provided on the second connector, wherein thepenetrating pin is a metallic conductor for inserting into the hollowpenetrating pin.

An impedance controlled mechanism is provided according to oneembodiment of the present invention. The impedance controlled mechanismis applied to a circuit board and related structure. The impedancecontrolled mechanism includes a metallic conductor, a dielectric layercovering the outer surface of the metallic conductor, and a metalshielding layer covering the outer surface of the dielectric layer.

A communication device is provided according to one embodiment of thepresent invention. The communication device includes a circuit boardinterconnection system. The system includes a first circuit board, asecond circuit board, a third circuit board, a first connector and asecond connector. The first connector and the second connector aremounted at two sides of the first circuit board, respectively. Thesecond circuit board is mounted on the first connector. The thirdcircuit board is mounted on the second connector. The first connectorand the second connector mounted respectively at two sides of the firstcircuit board are coupled via an impedance controlled mechanism on thefirst circuit board.

A method for manufacturing a circuit board is provided according to anembodiment of the present invention. The method includes:

mounting an impedance controlled mechanism on the circuit board, whereinthe impedance controlled mechanism is configured to connect connectorsmounted at two sides of the circuit board.

Therefore, the present invention enjoys the below benefits.

The circuit board adopts the impedance controlled mechanism which has ashielding function and an impedance controlled function to realize thefunction of a via hole, i.e., replace an impedance-uncontrolled via holeon the existing circuit board. Since the impedance value of theimpedance controlled mechanism is set based on the actual circuitenvironment and the impedance is stable and not subject to interference,the impedance inconsistency due to the metallized via hole and thecrosstalk among each interconnection path can be overcome when thesignal is transmitted via the impedance controlled mechanism. Thus, thetransmission performance of the circuit board interconnection system andthe circuit board is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a mounting schematic of an existing backplane interconnectionsystem;

FIG. 2 is a mounting schematic of an via connection section on anexisting backplane interconnection system;

FIG. 3 is a mounting schematic of an existing orthogonal backplaneinterconnection system;

FIG. 4 a is a front view of an existing orthogonal backplaneinterconnection system;

FIG. 4 b is a cross-section view of the front card in FIG. 4 a;

FIG. 4 c is a right view of an existing orthogonal backplaneinterconnection system;

FIG. 5 a is front view of a master-slave circuit board interconnectionsystem according to one embodiment of the present invention;

FIG. 5 b is a cross-section view of a cable and an impedance controlledmechanism in FIG. 5 a;

FIG. 5 c is a right view of FIG. 5 a;

FIG. 6 a illustrates mounting areas for backplane connectors, and thearrangement of pads and impedance controlled mechanisms within themounting areas according to one embodiment of the present invention;

FIG. 6 b illustrates the arrangement of pads and impedance controlledmechanisms on the backplane according to one embodiment of the presentinvention;

FIG. 7 a is a first schematic of an impedance controlled mechanismaccording to a first embodiment of the present invention;

FIG. 7 b is a second schematic of an impedance controlled mechanismaccording to a first embodiment of the present invention;

FIG. 8 a is a first schematic of an impedance controlled mechanismaccording to a second embodiment of the present invention;

FIG. 8 b is a second schematic of an impedance controlled mechanismaccording to a second embodiment of the present invention;

FIG. 9 is a mounting structure schematic of a backplane interconnectionsystem according to a first embodiment of the present invention;

FIG. 10 is a mounting structure schematic of a backplane interconnectionsystem according to a second embodiment of the present invention;

FIG. 11 is a mounting structure schematic of a backplane interconnectionsystem according to a third embodiment of the present invention;

FIG. 12 is a first mounting structure schematic of a backplaneinterconnection system according to a fourth embodiment of the presentinvention;

FIG. 13 is a second mounting structure schematic of a backplaneinterconnection system according to a fourth embodiment of the presentinvention;

FIG. 14 is a first mounting structure schematic of a backplaneinterconnection system according to a fifth embodiment of the presentinvention;

FIG. 15 is a second mounting structure schematic of a backplaneinterconnection system according to a fifth embodiment of the presentinvention;

FIG. 16 is a mounting structure schematic of a backplane interconnectionsystem according to a sixth embodiment of the present invention; and

FIG. 17 is an illustration of a coplanar processing for cables andcircuit board surface according to a sixth embodiment of the backplaneinterconnection system of the present invention.

DETAILED DESCRIPTION

The purposes, technical solutions and advantages concerning theembodiments of the present invention will become more readilyappreciated by reference to the following description of theembodiments.

In the embodiments of the present invention, a structure which has ashielding function and an impedance controlled function is used torealize via holes, i.e., to replace via holes on the existing circuitboard. Meanwhile, in the embodiments of the present invention,high-speed cables also can be used to realize the high-speeddifferential signal lines on each slave circuit board for coupling tothe circuit board connectors.

The high-speed cables may be twisted pair cables, coaxial cables,parallel cables, etc.

The circuit board interconnection system according to one embodiment ofthe present invention may include a first circuit board, a secondcircuit board, a third circuit board, a first connector and a secondconnector.

The first connector and the second connector are mounted on two sides ofthe first circuit board respectively in such a way that the secondcircuit board on the first connector mounted at one side of the firstcircuit board is perpendicular to the third circuit board on the secondconnector mounted at the other side of the first circuit board.

The first connector and the second connector mounted at two sides of thefirst circuit board are coupled to each other via an impedancecontrolled mechanism on the first circuit board.

Embodiments are illustrated by way of a backplane interconnection systemas the circuit board interconnection system, a backplane as the firstcircuit board, a front card/rear card (“/” hereinafter refers to “or”)as the second circuit board, a rear card/front card as the third circuitboard, backplane connectors as the first connector and the secondconnector.

Referring to FIGS. 5 a˜5 c, FIG. 5 a is a front view of a circuit boardinterconnection system according to one embodiment of the presentinvention. FIG. 5 b is cross-section view of cable 54 and impedancecontrolled mechanism 32 shown in FIG. 5 a.

FIG. 5 c is a right view of a circuit board interconnection systemaccording to one embodiment of the present invention. As illustrated inFIGS. 5 a˜5 c, the circuit board interconnection system according to oneembodiment of the present invention may include a front card 301, a rearcard 302, a backplane connector 31, a backplane connector 32 and abackplane 300.

The backplane connector 31 and the backplane connector 32 are mounted atthe two sides of the backplane 300, respectively, and these twoconnectors are coupled by the impedance controlled mechanism 53 on thebackplane 300.

If an orthogonal mounting structure is utilized in the backplaneinterconnection system, the front card 301 and the rear card 302 may bemounted respectively on the backplane connector 31 and the backplaneconnector 32 which are at two sides of the backplane 300. The front card301 and the rear card 302 are orthogonal to each other.

In this case, if there are multiple front cards and/or multiple rearcards, the multiple front cards may be arranged in parallel and themultiple rear cards may be arranged in parallel.

In addition, the front card 301 and the rear card 302 are mounted with adriver 311 and a receiver 321, respectively. The driver 311 on the frontcard 301 and the receiver 312 on the rear card 302 are respectivelycoupled to the backplane connector 31 and the backplane connector 32 viathe cable 54.

In the above system, the driver 311 and the receiver 321 (chip) are bothreferred to as transceivers. The cable 54 between the driver311/receiver 321 and the back connector 31/32 may be implemented invarious forms. The impedance controlled mechanism 53 may also beimplemented in various ways.

In the above system, there may be one pair of the front card and therear card and one pair of their corresponding transceivers.Alternatively, there may be a plurality of pairs of the front card andthe rear card and a plurality of pairs of their correspondingtransceivers, in which each pair may be mounted according to the abovemethod.

In the present embodiment, if an orthogonal mounting structure isutilized in the backplane interconnection system, an array of impedancecontrolled mechanisms 53 may be arranged in diagonal symmetry in orderto eliminate the necessity to deploy signal lines on the backplane 300which would have otherwise affected the performance of eachinterconnection path.

Diagonal symmetry refers to that the array is symmetric along thediagonal of the mounting area for the backplane connector.

FIG. 6 a illustrates arrangement of mounting areas for backplaneconnectors and the pads and impedance controlled mechanisms within themounting areas. As illustrated in FIG. 6 a, the blocks in solid linedenote slots for the front card 301 while the blocks in dash and dotline denote slots for the rear card 302. The positions of the slots forthe front card 301 are orthogonal to the slots for the rear card 302.Take 4*4 pairs of backplane connectors in the orthogonal backplaneinterconnection system as an example. A1Y, B1Y, . . . G4Y, H4Y denotesignal pins of the backplane rear card. A1X, B1X, . . . G4X, H4X denotesignal pins of the backplane front card. The signal pins are arranged indiagonal symmetry. In a same mounting area, i.e., the area where a frontcard 301 slot and a rear card 302 slot overlaps, the pads (or pins) andthe impedance controlled mechanisms at two sides of the diagonal of themounting area are symmetric along the diagonal of the mounting area.

As illustrated in FIG. 6 a, a solid black circle with a circle outsidedenotes an impedance controlled mechanism 53. The impedance controlledmechanisms 53 are arranged in diagonal symmetry. The solid black circlewithout a circle outside denotes ground pins on the backplane, which maybe metallized via holes for connecting the backplane connectors to theground of the backplane.

FIG. 6 b illustrates arrangement of pads and impedance controlledmechanisms on the backplane according to one embodiment of the presentinvention. As illustrated in FIG. 6 b, the backplane includes aplurality of mounting areas for backplane connectors. The pads andmounted impedance controlled mechanisms in each mounting area arearranged in a way as illustrated in FIG. 6 a, i.e., being symmetricalong the diagonal of the area.

The impedance controlled mechanism and a process for manufacturing abackplane having impedance controlled mechanism thereon will bediscussed in detail according to embodiments of the present invention.

A First Embodiment of an Impedance Controlled Mechanism and a Processfor Manufacturing a Backplane Having the Impedance Controlled MechanismThereon

In the present embodiment, the impedance controlled mechanism 53 mayinclude from inside to outside a shielding layer, a dielectric layer,and a metallic conductor. In practice, the shielding layer, thedielectric layer and the metallic conductor can be provided by variousmaterial.

The shielding layer and the dielectric layer are closing layers with acontinuous side. The metallic conductor may be in a solid or hollowform, or other forms.

FIG. 7 a is a first schematic of an impedance controlled mechanismaccording to the first embodiment of the present invention. Asillustrated in FIG. 7 a, a first type of impedance controlled mechanismaccording to the present embodiment includes a metallic conductor 532 awith a dielectric (dark part refers to the metallic conductor and theundertint part refers to the dielectric surrounding the metallicconductor) and a metallized via hole 531 on the backplane. Themetallized via hole 531 serves as a shielding layer for the impedancecontrolled mechanism. The metallic conductor 532 a with the dielectricis inserted in the metallized via hole 531, with two ends being alignedwith the surfaces of the backplane 300.

The resistance value can be determined once the size of the metallicconductor 532 a with the dielectric, the inner diameter of themetallized via hole 531 and the relative dielectric constant for thedielectric are determined. Thus, the impedance is controllable. Takecoaxial structure in FIG. 7 a as an example of the impedance controlledmechanism. The relation between the impedance Z and the size of thestructure may be defined as follow.

$Z = {\frac{60}{\sqrt{ɛ_{r}}}{\ln ( \frac{d_{2}}{d_{1}} )}}$

where Z denotes impedance, ∈_(r) denotes relative dielectric constantfor the dielectric, d₂ denotes the inner diameter of the metallized viahole 531 in cylindric shape and d₁ denotes the outer diameter of acylindric metallic conductor which has been pressed into the metallizedvia hole (see the dark part of the metallic conductor 532 a with thedielectric in FIG. 7 a).

In the first type of impedance controlled mechanism as illustrated inFIG. 7 a, the metallic conductor 532 a with the dielectric is a solidsubstance. The metallic conductor can also be a hollow substance.

FIG. 7 b is a second schematic of an impedance controlled mechanismaccording to the first embodiment of the present invention. Asillustrated in FIG. 7 b, in a second type of impedance controlledmechanism according to the present embodiment, the metallic conductor532 b with a dielectric (the dark part denotes the metallic conductor,the colorless part denotes the dielectric, and the metallic conductor ishollow) is a hollow substance.

For the second type of impedance controlled mechanism as illustrated inFIG. 7 b, the relation between the impedance Z and the size of thestructure may be defined as follow.

$Z = {\frac{60}{\sqrt{ɛ_{r}}}{\ln ( \frac{d_{2\;}}{d_{1}} )}}$

where Z denotes impedance, ∈_(r) denotes relative dielectric constantfor the dielectric, d₂ denotes the inner diameter of the metallized viahole 531 in cylindric shape and d₁ denotes the outer diameter of acylindric hollow metallic conductor which has been pressed into themetallized via hole (see the dark part of the metallic conductor 532 bwith the dielectric in FIG. 7 b).

Compared with the first type of impedance controlled mechanism in FIG. 7a, a second type of impedance controlled mechanism supports a backplaneconnector with pin connections while the first type of impedancecontrolled mechanism is preferably applicable to surface-mount backplaneconnectors for mounting on the two ends of the first type of impedancecontrolled mechanism.

A backplane 300 having the impedance controlled mechanism shown in FIGS.7 a and 7 b can be manufactured in the following way.

a. A metallized via hole 531 is manufactured on the backplane accordingto traditional manufacturing approach.

In this step, the metallized via hole 531 is manufactured on thebackplane at a position relative to the backplane connector to bemounted, e.g., the position relative to the pins of the backplaneconnector for transmitting high-speed data.

b. The metallic conductor 532 with the dielectric is pressed into themetallized via hole 531.

In this step, a force F parallel to the axis of the metallized via holeis applied in order to press the metallic conductor 532 with thedielectric into the metallized via hole 531.

c. Mechanical manufacturing is employed in order to ensure that the endface of each impedance controlled mechanism on the backplane is in asame plane with the backplane surface.

In this step, in a direction parallel to the backplane surface, a metalcutting tool 70 with an angular velocity w and a feed rate V is used tocut the portion of the impedance controlled mechanism which protrudesout of the backplane surface.

d. The surface is processed as desired. For instance, the surface may beprocessed by way of Immersion Silver, Immersion Tin, or goldelectroplate, etc.

If the metallic conductor 532 with the dielectric has a length greaterthan the thickness of the backplane, the two ends of the metallicconductor 532 with the dielectric may be extruded outside the backplanesurface after the metallic conductor 532 with the dielectric is pressedinto the metallized via hole 531 on the backplane. Therefore, mechanicalmanufacturing or other manufacturing method is required to be applied ontwo sides of the backplane to ensure that the ends of the impedancecontrolled mechanism are aligned with the backplane surfaces.Alternatively, after the metallic conductor 532 with the dielectric ispressed into the metallized via hole 531 on the backplane, the metallicconductor 532 with the dielectric may be such that one end of theconductor is extruded outside the backplane surface while the other endis inside the backplane surface with a distance apart from the backplanesurface. Thus, one end of the metallized via hole 531 is ensured toreserve a space inside for insertion of various connection mechanismssuch as a press-fit pin so that the backplane and backplane connectorare coupled in press-fit manner. Then, mechanical manufacturing isrequired only on one side of the backplane to ensure that the end faceof the impedance controlled mechanism is aligned with the backplanesurface. As such, the backplane may be connected with a backplaneconnector in a surface-mount manner at a side where the impedancecontrolled mechanism is aligned with the backplane surface while beingconnected with a backplane connector, for example, in a press-fit mannerat the other side where the metallized via hole 531 reserves a spaceinside.

If the metallic conductor 532 with the dielectric has a length less thanthe thickness of the backplane, the metallic conductor 532 with thedielectric can be pressed into the metallized via hole 531 on thebackplane by using a knock pin having a diameter less or equal to theinner diameter of the metallized via hole 531. Thus, the two ends of themetallic conductor 532 with the dielectric are both located within thebackplane surface with the two ends each spaced a distance apart fromthe surface of the backplane. In this way, each end of the innermetallized via hole 531 reserve a space inside for insertion of variousconnection mechanisms such as a press-fit pin. Thus, the two sides ofthe backplane may be coupled to the backplane connectors, for example,in a press-fit manner. In this case, no mechanical manufacturing isrequired to keep the ends of the impedance controlled mechanism alignedwith the backplane surfaces.

Thus, a backplane including an impedance controlled mechanism can bemanufactured.

In the above solution, the process for manufacturing the backplane mayinclude the step of pressing the metallic conductor 532 with thedielectric. In the present embodiment, this step can be replaced by anapproach accommodating a traditional method for manufacturing printedslave circuit board.

A Second Embodiment of an Impedance Controlled Mechanism and a Processfor Manufacturing a Backplane Having the Impedance Controlled MechanismThereon

FIG. 8 a is a first schematic of an impedance controlled mechanismaccording to the second embodiment of the present invention. FIG. 8 b isa second schematic of an impedance controlled mechanism according to thesecond embodiment of the present invention;

As illustrated in FIGS. 8 a and 8 b, if the backplane can be processedwith an approach accommodating a traditional method for manufacturingslave circuit board, the first type of impedance controlled mechanismmanufactured on the backplane may include a metallized via hole 531 onthe backplane, insulated material 534 on the inner wall of themetallized via hole 531 (or may be referred to as non-metallized viahole in the metallized via hole 531) and conductor material 535a/conductor material 535 b. The metallized via hole 531 is served as ashielding layer of the impedance controlled mechanism. Thenon-metallized via hole 534 is served as the dielectric layer of theimpedance controlled mechanism. The conductive material 535 a and theconductive material 535 b are non-solid state material such as liquid orpowder, which are served as the metallic conductor of the impedancecontrolled mechanism.

Referring to FIG. 8 a, the conductive material 535 a is filled in thenon-metallized via hole 534. The non-metallized via hole 534 is insertedinto the metallized via hole 531 on the backplane and the end face ofthe non-metallized via hole 534 is in a same plane with the surface ofthe backplane 300. The conductive material 535 a should not beoverflowed onto the surface of the backplane 300.

Referring to FIG. 8 b, the conductive material 535 a is covered on theinner wall of the non-metallized via hole 534. The non-metallized viahole 534 is inserted into the metallized via hole 531 on the backplaneand the end face of the non-metallized via hole 534 is in a same planewith the surface of the backplane 300. The conductive material 535 bshould not be overflowed onto the surface of the backplane 300.

The impedance value can be determined once the inner diameter of themetallized via hole 531 c, the inner diameter of the non-metallized viahole 534 and the relative dielectric constant for the dielectric aredetermined. Thus, the impedance is controllable. The relation betweenimpedance Z and the size can refer to the impedance controlled mechanismillustrated in FIGS. 7 a and 7 b.

A backplane 300 having the impedance controlled mechanism thereon asillustrated in FIGS. 8 a and 8 b can be manufactured in the followingway.

a. A traditional metallized via hole 531 is manufactured on thebackplane.

In this step, the metallized via hole 531 is manufactured on thebackplane at a position relative to the backplane connector to bemounted, e.g., the position relative to the pins of the backplaneconnector for transmitting high-speed data.

b. The insulated material 533 is injected to the via hole 531. By way ofexample, the insulated material may be insulated resin for use in theprinted slave circuit board.

c. The non-metallized via hole 534 having a corresponding inner diameteris manufactured in the insulated material according to the impedancerequirement.

d. A conductive material 535 a (solid structure) is injected into thenon-metallized via hole as required. Alternatively, the non-metallizedvia hole 534 can be metallized using an electroplate approach. That is,the inner wall of the non-metallized via hole 534 is covered withconductive material 535 b (hollow structure).

In practice, between step b and step c or after step d, a part of theinsulated material 533 in the metallized via hole 531 at one end or twoends can be removed by mechanical manufacturing such as by perforationor other manufacturing method. Thus, one end or two ends of themetallized via hole 531 may have a space for insertion of variousconnection mechanisms such as a press-fit pin so that the backplane andbackplane connector can be connected in press-fit manner. Consequently,the backplane may be coupled to the backplane connector in asurface-mount manner or in a press-fit pin manner, for example.

Thus, a backplane including an impedance controlled mechanism can alsobe manufactured.

On the backplane, the impedance controlled mechanism is used to replacethe traditional metallized via hole. Since the impedance value of theimpedance controlled mechanism is set based on the actual circuitenvironment and the impedance is stable and is not subject tointerference, the issue of impedance incontinuity as a result of thetraditional via hole can be overcome when the signal is transmitted viathe impedance controlled mechanism. Meanwhile, since the impedancecontrolled mechanism has a metal shielding layer outside, crosstalkamong the impedance controlled mechanism in each interconnection pathcan be eliminated, which overcomes the prior art problem of crosstalkamong the interconnection paths due to the crosstalk among the via holeson the backplane.

Detailed explanation is made to various backplane interconnectionsystems in various embodiments considering the different connectionapproaches for connecting between the cables and the driver/receiver andbetween the cables and the backplane connectors, and the approach forconnecting backplane connectors at two sides of the backplane. Thefollowing embodiments are focused on orthogonal backplaneinterconnection system. Pads within the mounting areas for the backplaneconnectors on the backplane may also be arranged in diagonal symmetry asdescribed above. The impedance controlled mechanisms mounted on thebackplane may be in the form as illustrated in FIG. 7 a, or 7 b or 8 aor 8 b, or in other form. A corresponding mounting method is employedfor mounting the impedance controlled mechanisms onto the backplane.

A First Embodiment of the Backplane Interconnection System

In this embodiment, the connection between the cable and thedriver/receiver and the connection between the cable and the backplaneconnectors are implemented by cable connectors and a press-fit pinmechanism. The backplane connectors are coupled to the backplane via thepress-fit pin mechanism.

FIG. 9 is a mounting structure of a backplane interconnection systemaccording to a first embodiment of the present invention; as illustratedin FIG. 9, the backplane interconnection system according to the presentembodiment may include a front card 301, a driver 311 on the front card301, a backplane 300, a rear card 302, a receiver 321 on the rear card302, a backplane connector 31, a backplane connector 32 and cableconnectors 55.

The front card 301/rear card 302 is perpendicular to the backplane 300and the front card 301 is orthogonal to the rear card 302.

The cable connectors 55 are mounted on the front card 301/rear card 302and are not at the same side with the driver 311/receiver 321 on thefront card 301/rear card 302. Moreover, the driver 311/receiver 321 andthe backplane connector 31/32 are located at the same side of the frontcard 301/rear card 302.

Two ends of the cable 54 are coupled to two cable connectors 55,respectively. The cable connector at one end of the cable 54 ispress-fitted via a press-fit pin 56 into the via hole 312/322 welded tothe driver 311/receiver 321. The cable connector 55 at the other end ofthe cable 54 and the backplane connector 31/32 are press-fitted via thepress-fit pin 56 into the same via hole 314/324 on the front card301/rear card 302. In addition, the other end of the press-fit pin 56 inthe backplane connector 31/32 penetrates from the side where thebackplane connector 31/32 contacts the front card 301/rear card 302 tothe side where the backplane connector 31/32 contacts the backplane 300and is press-fitted into the impedance controlled mechanism 53 on thebackplane 300. Therefore, the driver 311/receiver 321 is coupled to thebackplane connector 31/32 via the cable connector 55 and the cable 54.

In the present embodiment, because the backplane connector 31/32 iscoupled to the impedance controlled mechanism 53 via the press-fit pin,the impedance controlled mechanism 53 in the present embodiment ispreferably in the form of a hollow impedance controlled mechanism asillustrated in FIG. 7 b or 8 b. If the solid impedance controlledmechanism as illustrated in FIG. 7 a is adopted, the metallic conductor532 with the dielectric in this structure should have a length shorterthan the thickness of the backplane so that one end of the press-fit pincan be inserted. If the solid impedance controlled mechanism asillustrated in FIG. 8 a is adopted, the room for inserting the press-fitpin 56 should be reserved likewise.

In practice, the cable 54 mounted on the cable connectors 55 may be in aconductive connection with the press-fit pin 56 in various manners. Forinstance, the cable 54 may be in conductive connection with thepress-fit pin 56 via the via hole in the cable connector 55 or bywelding a conducting wire to the end where the press-fit pin 56 ispress-fitted to the cable connector 55.

Thus, the interconnection path from the driver 311 to the backplane 300sequentially goes through the via hole 312 on the front card 301, thecable connector 55, the cable 54, the cable connector 55, the via hole314 on the front card 301, the impedance controlled mechanism 53coupling the backplane connector 31 to the backplane. Theinterconnection path from the receiver 321 to the backplane 300 issimilar.

Therefore, in the backplane interconnection system according to thepresent embodiment, the signal is transmitted via the cable 54 on thefront card 301 and the rear card 302 and the impedance controlledmechanism 53 on the backplane 300 instead of being transmitted via thedifferential signal line 313/323 on the front card 301/rear card 302 andthe signal line and the via hole 30 on the backplane according to aconventional solution. Compared with the signal transmitted through thedifferential signal line, the signal transmitted through the high-speedcable may be subject to lessened signal attenuation and the signaltransmission delay is stable. Therefore, the signal attenuation on eachinterconnection path is minor and the delay on each interconnection pathis substantially the same. Because the impedance value of the impedancecontrolled mechanism on each interconnection path is set depending onthe actual circuit environment, the impedance is stable and is notsubject to interference. Thus, the impedance continuity for eachinterconnection path is enhanced. Moreover, because the impedancecontrolled mechanism has a shielding layer, each interconnection pathincluding the impedance controlled mechanism may not suffer from thecrosstalk caused by the via hole on the backplane according to theconventional solution.

Furthermore, in the present embodiment, a press-fit pin method is usedfor connection. The connection method is a conventional technicalsolution which is easy to accomplish. In addition, with this connectionmethod, each component in the backplane interconnection system can bemounted and demounted flexibly.

In the backplane interconnection system of the present embodiment, oneor more connection mechanisms employing the press-fit pin method may bereplaced with other connection mechanism described in the followingembodiments of the backplane interconnection system. It is to be notedthat not all of the connection mechanisms in the system need to take theform of such connection mechanism.

A Second Embodiment of the Backplane Interconnection System

In the present embodiment, the backplane connectors are connected to thebackplane in a surface-mount manner. For instance, welding orpressure-fit connection can be employed. Considering the elastic pin ofthe connector, a force is applied on the connector so as to ensure thatthe signal pins of the connector is in conductive connection with theimpedance controlled path on the backplane.

FIG. 10 is a mounting structure of a backplane interconnection systemaccording to a second embodiment of the present invention. Asillustrated in FIG. 10, in the backplane interconnection systemaccording to the present embodiment, one end of the impedance controlledmechanism 53 on the backplane 300 may be welded to a surface-mountsignal pin 57. The surface-mount signal pin 57 may also be coupled tothe impedance controlled mechanism 53 by virtue of a spring 58 and be incontact with the impedance controlled mechanism 53 by a pressure appliedperpendicular to the surface of the backplane 300.

The surface-mount signal pin 57 coupled to the impedance controlledmechanism 53 is then coupled to the backplane connector 31/32, forinstance, by inserting into the backplane connector 31/32.

Because in the present embodiment, a surface-mount manner is utilized torealize the connection between the impedance controlled mechanism 53 andthe backplane connector 31/32, the impedance controlled mechanism 53 onthe backplane 300 is preferably in a solid structure as illustrated inFIG. 7 a or 8 a so as to ensure that the impedance controlled mechanism53 may fully contact the surface-mount signal pin 57.

Thus, the interconnection path between the backplane connector 31 andthe backplane connector 32 on the two sides of the backplane 300 goesthrough the surface-mount signal pin 57, the impedance controlledmechanism 53 and the surface-mount signal pin 57.

Therefore, in the backplane interconnection system according to thepresent embodiment, the signal is transmitted via the impedancecontrolled mechanism 53 on the backplane 300 instead of beingtransmitted via the differential signal line 313/323 and the via hole 30on the backplane 300 according to a conventional solution. Because theimpedance value of the impedance controlled mechanism in eachinterconnection path is set depending on the actual circuit environment,the impedance is stable and is not subject to interference. Thus, theimpedance continuity for each interconnection path is enhanced.Moreover, because the impedance controlled mechanism has a shieldinglayer, each interconnection path including the impedance controlledmechanism may not suffer from the crosstalk caused by the via hole onthe backplane according to the conventional solution.

Moreover, because in the present embodiment a surface-mount manner isemployed for the connection, the backplane does not need to be verythick, which reduces the system cost.

In the present embodiment, the backplane connector is coupled to thebackplane in a surface-mount manner. A press-fit pin manner as describedin the first embodiment of the backplane interconnection system may beutilized in the other connection mechanism. Alternatively, otherconnection method as will be described in the following embodiment ofthe backplane interconnection system can be utilized.

A Third Embodiment of the Backplane Interconnection System

In the present embodiment, the impedance controlled mechanism may bedivided into two parts which are arranged respectively on the twobackplane connectors at the two sides of the backplane.

FIG. 11 is a mounting structure schematic diagram of a backplaneinterconnection system according to a third embodiment of the presentinvention. As illustrated in FIG. 11, an example that two backplaneconnectors are coupled to each other via two impedance controlledmechanisms is provided. In the backplane interconnection systemaccording to the present embodiment, the backplane 300 includes athrough hole 59. The backplane connector 31/32 on one side of thebackplane 300 includes two hollow penetrating pin portions 538 and thebackplane connector 32/31 on the other side of the backplane 300includes two penetrating pin portions 539.

The hollow penetrating pin portions 538 and penetrating pin portions 539are located respectively at a position on the backplane connector 31/32and the backplane connector 32/31 for transmitting signal. The hollowpenetrating pin portion 538 on the backplane connector 31/32 is a hollowsubstance made from metal material (for example, a hollow cylinder in acoaxial structure, i.e., the hollow portion can also be in a cylindershape). The outer size (outer diameter) of the hollow penetrating pinportion 538 may be smaller than the size of the through hole 59 on thebackplane. The inner wall may be covered with a dielectric layer (darkportion). The penetrating pin portion 539 on the other backplaneconnector 32/31 is a metallic conductor (e.g., a metallic conductor in acylinder shape. The conductor may be a solid substance, such as acylinder, or may be a hollow substance in a coaxial structure). Theouter size (outer diameter) of the penetrating pin portion 539 may besmaller than or equal to the inner size (inner diameter) of thedielectric layer of the hollow penetrating pin portion 538.

The inner wall of the dielectric layer of the hollow penetrating pinportion 538 may also be covered with a metallic conductor layer (themetallic conductor layer is in conductive connection with acorresponding portion on the backplane connector 31/32, for instance,the portion for transmitting signals). Thus, the penetrating pin portion539 inserting into the hollow penetrating pin portion 538 may be inconductive connection with the backplane connector 31/32 with the hollowpenetrating pin and the backplane connector 32/31 with the penetratingpin by virtue of the metallic conductor layer and the bottom (metalmaterial) of hollow penetrating pin portion 538.

Alternatively, the bottom of the hollow penetrating pin portion 538 (theposition corresponding to the associated portion of the backplaneconnector 32/31) is mounted with a metal spring contact. The end of theinserted penetrating pin portion 539 can be in contact with the metalspring contact. Thus, the backplane connector 31/32 with a hollowpenetrating pin can be in conductive connection with the backplaneconnector 32/31 with the penetrating pin.

Alternatively, the penetrating pin portion 539 is ensured to have alength which is the same as the depth of the hollow penetrating pinportion 538 so that the end of the inserted penetrating portion 539 canbe in contact with the bottom of the hollow penetrating pin portion 538(the position corresponding to the associated portion of the backplaneconnector 32/31). As a result, the backplane connector 31/32 with thehollow penetrating pin is in conductive connection with the backplaneconnector 32/31 with the penetrating pin.

In the above three solutions for connecting the hollow penetrating pinand the penetrating pin portion, the one with a metallic conductor layercovering the dielectric layer has the highest reliability.

At the through hole 59 on the backplane, the penetrating pin portion 539is inserted under a pressure F into the dielectric layer of the hollowpenetrating pin portion 538. That is, a connector assembly including thebackplane connector 31 and the backplane connector 32 constitutes theimpedance controlled mechanism including a shielding layer, dielectriclayer and metallic conductor. At the meantime, the connection betweenthe backplane connector 31 and the backplane connector 32 is realized.

Thus, the interconnection path between the backplane connectors on twosides of the backplane only includes an impedance controlled mechanism.

Therefore, in the backplane interconnection system according to thepresent embodiment, the signal is transmitted via an impedancecontrolled mechanism 53 including a hollow penetrating pin portion 538on the backplane connector 31/32 and a penetrating pin portion 539 onthe backplane connector 32/31 instead of being transmitted via thedifferential signal line 313/323 and the via hole 30 on the backplaneaccording to a conventional solution. Because the impedance value of theimpedance controlled mechanism in each interconnection path is setdepending on the actual circuit environment, the impedance is stable andis not subject to interference. Thus, the impedance continuity for eachinterconnection path is enhanced. Moreover, because the impedancecontrolled mechanism has a shielding layer, each interconnection pathincluding the impedance controlled mechanism may not suffer from thecrosstalk caused by the via hole on the backplane according to theconventional solution.

Moreover, the present embodiment eliminates the necessity to mount theimpedance controlled mechanism on the backplane and thus simplifies theprocess for manufacturing the backplane by providing a hollowpenetrating pin portion 538 and a penetrating pin portion 539 on twobackplane connectors at two sides of the backplane.

In the present embodiment, the backplane connectors at two sides of thebackplane are coupled together by a hollow penetrating pin portion and apenetrating pin portion. In the other connection mechanism, a press-fitpin structure may be utilized as described in the first embodiment ofthe backplane interconnection system. Alternatively, other connectionmethod as will be described in the following embodiments of thebackplane interconnection system can be utilized.

A Fourth Embodiment of the Backplane Interconnection System

In the present embodiment, various traditional surface-mount structuressuch as Ball Grid Array (BGA) are adopted in the receiver (chip). Thecable is let out of a pad of a chip pin by virtue of a microstrip whichis then coupled to the cable via the cable connector.

FIG. 12 is a first mounting structure of a backplane interconnectionsystem according to the fourth embodiment of the present invention. Asillustrated in FIG. 12, the backplane interconnection system accordingto the present embodiment may include a front card 301, a driver 311 onthe front card 301, a backplane 300, a rear card 302, a receiver 321 onthe rear card 302, a backplane connector 31, a backplane connector 32and a cable connector 55.

The front card 301/rear card 302 is perpendicular to the backplane 300and the front card 301 is orthogonal to the rear card 302.

The cable connector 55, the driver 311/receiver 321, and the backplaneconnector 31/32 are located at the same side of the front card 301/rearcard 302.

The driver 311/receiver 321 is coupled to the backplane connector 31/32via the cable connector 55 and the cable 54. Two ends of the cable 54are coupled to two cable connectors 55, respectively. The cableconnector 55 at one end of the cable 54 is coupled via a microstrip 60(by welding) to the pad of the pin of the driver 311/receiver 321 (e.g.,pin of the data bus). The cable connector 55 at the other end of thecable 54 is mounted on the surface where the backplane connector 31/32is perpendicular to the front card 301/rear card 302 and on the surfacewhich is close to the driver 311/receiver 321.

The cable connector 55 mounted on the backplane connector 31/32 iscoupled to the press-fit pin 56 in the impedance controlled mechanism 53press-fitted on the backplane 300 by penetrating the conducting wire ofthe backplane connector 31/32. In the present embodiment, the backplaneconnector 31/32 may be coupled to the impedance controlled mechanism 53on the backplane 300 in a manner described in the second embodiment orthe third embodiment. In this case, the cable connector 55 mounted onthe backplane connector 31/32 is coupled to the surface-mount signal pin57 on the backplane 300 or coupled to the hollow penetrating pin portion538/penetrating pin portion 539 on the backplane connector 31/32 bypenetrating the conducting wire of the backplane connector 31/32.

FIG. 13 is a second mounting structure of a backplane interconnectionsystem according to the fourth embodiment of the present invention. Asillustrated in FIG. 13, in the backplane interconnection systemaccording to the embodiment of the present invention, the cableconnector 55 may not be coupled to the pads of the driver 311/receiver321 (chip) to realize the connection with the driver 311/receiver 321.Rather, the cable connector 55 may be mounted on the top of the driver311/receiver 321 (chip) so that the cable 54 can be directly led out ofthe pin (e.g., the pin of the data bus) by virtue of a microstrip likestructure, i.e., in a surface-mount manner.

Thus, the interconnection path from the driver 311 to the backplane 300sequentially goes through the cable connector 55 on the front card 301,the cable 54, the cable connector 55, the backplane connector 31, to theimpedance controlled mechanism 53. The interconnection path from thereceiver 321 to the backplane 300 is similar.

Therefore, in the backplane interconnection system according to thepresent embodiment, the signal is transmitted via the cable 54 on thefront card 301 and rear card 302 and the impedance controlled mechanism53 on the backplane 300 instead of being transmitted via thedifferential signal line 313/323 on the front card 301/rear card 302 andthe signal line and the via hole 30 on the backplane 300 according to aconventional solution. Compared with the signal transmitted through thedifferential signal line, the signal transmitted through the high-speedcable may be subject to lessened signal attenuation and the signaltransmission delay is stable. Therefore, the signal attenuation on eachinterconnection path is minor and the delay on each interconnection pathis substantially the same. Because the impedance value of the impedancecontrolled mechanism on each interconnection path is set depending onthe actual circuit environment, the impedance is stable and is notsubject to interference. Thus, the impedance continuity for eachinterconnection path is enhanced. Moreover, because the impedancecontrolled mechanism has a shielding layer, each interconnection pathincluding the impedance controlled mechanism may not suffer from thecrosstalk caused by the via hole on the backplane according to theconventional solution.

Moreover, in the present embodiment, the cable, driver 311/receiver 321and the backplane connector 31/32 are mounted at the same side of thefront card 301/rear card 302. One end of the cable is directly coupledto the driver 311/receiver 321 without going through the front card301/rear card 302. A press-fit pin manner is employed on the other endof the cable for the connection. The signal transmitted does not need togo through the via hole on the front card 301/rear card 302, whichfurther minimizes the interference on the interconnection path, and thusenhancing the transmission performance of the interconnection path.

In the present embodiment, one or more connection mechanisms may also bereplaced by the connection mechanisms of the first embodiment or of thefollowing embodiments of the backplane interconnection system. It is tobe noted that not all of the connection mechanisms in the system need totake the form of such connection mechanism.

A Fifth Embodiment of the Backplane Interconnection System

In the present embodiment, the impedance controlled mechanism is used tosubstitute the via hole on the front card and the rear card as the slavecircuit board.

FIG. 14 is a first mounting structure of a backplane interconnectionsystem according to the fifth embodiment of the present invention. Asillustrated in FIG. 14, the backplane interconnection system accordingto the present embodiment may include a front card 301, a driver 311 onthe front card 301, a backplane 300, a rear card 302, a receiver 321 onthe rear card 302, a backplane connector 31, a backplane connector 32and a cable connector 55.

The front card 301/rear card 302 is perpendicular to the backplane 300and the front card 301 is orthogonal to the rear card 302.

The cable connectors 55 are mounted on the front card 301/rear card 302and are not at the same side with the driver 311/receiver 321 inrelative to the front card 301/rear card 302. Moreover, the driver311/receiver 321 and the backplane connector 31/32 are located at thesame side of the front card 301/rear card 302.

The two ends of the cable 54 are coupled to two cable connectors 55,respectively. The cable connector at one end of the cable 54 issurface-mounted on the impedance controlled mechanism 53 coupled (bywelding) to the driver 311/receiver 321. That is, the impedancecontrolled mechanism is used to replace the via hole 312/322 on thefront card 301/rear card 302. The cable connector 55 at the other end ofthe cable 54 and the backplane connector 31/32 are press-fitted via thepress-fit pin 56 into the same via hole 314/324 on the front card301/rear card 302. In addition, the other end of the press-fit pin 56 inthe backplane connector 31/32 penetrates from the side where thebackplane connector 31/32 contacts the front card 301/rear card 302 tothe side where the backplane connector 31/32 contacts the backplane 300and is press-fitted into the impedance controlled mechanism 53 on thebackplane 300. Therefore, the driver 311/receiver 321 is coupled to thebackplane connector 31/32 via the cable connector 55 and the cable 54.

In the present embodiment, if the backplane connector 31/32 is coupledto the impedance controlled mechanism 53 via the press-fit pin 56, theimpedance controlled mechanism 53 in the present embodiment ispreferably in the form of a hollow impedance controlled mechanism asillustrated in FIG. 7 b or 8 b. If the solid impedance controlledmechanism as illustrated in FIG. 7 a is adopted, the metallic conductorwith the dielectric in this structure should have a length shorter thanthe thickness of the backplane so that one end of the press-fit pin canbe inserted. If the solid impedance controlled mechanism as illustratedin FIG. 8 a is adopted, the room for inserting the press-fit pin shouldbe reserved likewise.

In practice, the cable 54 mounted on the cable connectors 55 may be in aconductive connection with the press-fit pin in various manners. Forinstance, the cable 54 may be in conductive connection with thepress-fit pin 56 via the via hole in the cable connector 55 or bywelding a conducting wire to the end where the press-fit pin 56 ispress-fitted to the cable connector 55.

FIG. 15 is a second mounting structure of a backplane interconnectionsystem according to the fifth embodiment of the present invention. Asillustrated in FIG. 15, the backplane interconnection system accordingto the present embodiment may include a front card 301, a driver 311 onthe front card 301, a backplane 300, a rear card 302, a receiver 321 onthe rear card 302, a backplane connector 31, a backplane connector 32and a cable connector 55.

The front card 301/rear card 302 is perpendicular to the backplane 300and the front card 301 is orthogonal to the rear card 302.

The second mounting structure illustrated in FIG. 15 differs from thefirst mounting structure illustrated in FIG. 14 in that the cableconnector 55 at the other end of the cable 54 does not use a press-fitpin 56 for connecting to the backplane connector 31/32. Rather, thesecond mounting structure illustrated in FIG. 15 is surface-mounted onthe impedance controlled mechanism 53 coupled (e.g., by welding) to thebackplane connector 31/32. That is, the impedance controlled mechanism53 is used to replace the via hole 314/324 on the front card 301/rearcard 302.

Thus, in the backplane interconnection system as illustrated in FIG. 14or FIG. 15, the interconnection path from the driver 311 to thebackplane 300 sequentially goes through the impedance controlledmechanism 53 on the front card 301, cable connector 55, the cable 54,the cable connector 55, the via hole 314 on the front card (firstmounting structure)/impedance controlled mechanism 53 (second mountingstructure), the impedance controlled mechanism 53 coupling the backplaneconnector 31 to the backplane. The interconnection path from thereceiver 321 to the backplane 300 is similar.

Therefore, in the backplane interconnection system according to thepresent embodiment, the signal is transmitted via the impedancecontrolled mechanism 53 and the cable 54 on the front card 301 and rearcard 302 and the impedance controlled mechanism 53 on the backplane 300instead of being transmitted via the via 312/322, the via 314/324, andthe differential signal line 313/323 on the front card 301/rear card 302and the signal line 313/323 and the via hole 30 on the backplane 300according to a conventional solution. Compared with the signaltransmitted through the differential signal line, the signal transmittedthrough the high-speed cable may be subject to a lessened signalattenuation and the signal transmission delay is stable. Therefore, thesignal attenuation on each interconnection path is minor and the delayon each interconnection path is substantially the same. Because theimpedance value of the impedance controlled mechanism on eachinterconnection path is set depending on the actual circuit environment,the impedance is stable and is not subject to interference. Thus, theimpedance continuity for each interconnection path is enhanced.Moreover, because the impedance controlled mechanism has a shieldinglayer, each interconnection path including the impedance controlledmechanism may not suffer from the crosstalk caused by the via hole onthe backplane according to the conventional solution.

Compared with other embodiment of the backplane interconnection system,the impedance controlled mechanism 53 on the front card 301/rear card302 is further employed in the present embodiment, which furtherimproves the continuity of the impedance and enhances the transmissionperformance of the interconnection path.

In the backplane interconnection system according to the presentembodiment, the impedance controlled mechanism 53 on the front card301/rear card 302 may also be replaced with other connection mechanismin the other embodiments of the backplane interconnection system. It isto be noted that not all of the connection mechanisms in the system needto take the form of such connection mechanism.

A sixth embodiment of the backplane interconnection system

In the present embodiment, the cable for connecting the driver/receiverand the backplane connector is buried in the front card 301/rear card302, and no cable connector is required.

FIG. 16 is a mounting structure of a backplane interconnection systemaccording to the sixth embodiment of the present invention. Asillustrated in FIG. 16, the backplane interconnection system accordingto the present embodiment may include a front card 301, a driver 311 onthe front card 301, a backplane 300, a rear card 302, a receiver 321 onthe rear card 302, a backplane connector 31, and a backplane connector32.

The front card 301/rear card 302 is perpendicular to the backplane 300and the front card 301 is orthogonal to the rear card 302. The backplaneconnector 31/32 is surface-mounted on the front card 301/rear card 302.

The cable 54 is buried in the front card 301/rear card 302, with one enddirectly coupling (e.g., by welding) to the pin (e.g., pin of the databus) of the driver 311/receiver 321. The other end of the cable 54penetrates from the side where the backplane connector 31/32 contactsthe front card 301/rear card 302 to the side where the backplaneconnector 31/32 contacts the backplane 300 and is coupled to thepress-fit pin 56 which is press-fitted to the impedance controlledmechanism 53 on the backplane 300.

In the present embodiment, if the backplane connector 31/32 is coupledto the impedance controlled mechanism 53 via the press-fit pin 56, theimpedance controlled mechanism 53 in the present embodiment ispreferably in the form of a hollow impedance controlled mechanismillustrated in FIG. 7 b or 8 b. If the solid impedance controlledmechanism as illustrated in FIG. 7 a is adopted, the metallic conductorwith the dielectric in this structure may have a length shorter than thethickness of the backplane so that one end of the press-fit pin can beinserted. If the solid impedance controlled mechanism as illustrated inFIG. 8 a is adopted, the room for inserting the press-fit pin 56 shouldbe reserved likewise.

Thus, the interconnection path from the driver 311 to the backplane 300goes through the cable 54 and the impedance controlled mechanism 53 fromthe backplane connector 31 to the backplane 300. The interconnectionpath from the receiver 321 to the backplane 300 is similar.

Therefore, in the backplane interconnection system according to thepresent embodiment, the signal is not transmitted via the differentialsignal line 313/323 on the front card 301/rear card 302 nor transmittedvia the signal line and the via hole 30 on the backplane 300. Comparedwith the signal transmitted through the differential signal line, thesignal transmitted through the high-speed cable may be subject to alessened signal attenuation and the signal transmission delay is stable.Therefore, the signal attenuation on each interconnection path is minorand the delay on each interconnection path is substantially the same.Because the impedance value of the impedance controlled mechanism oneach interconnection path is set depending on the actual circuitenvironment, the impedance is stable and is not subject to interference.Thus, the impedance continuity for each interconnection path isenhanced. Moreover, because the impedance controlled mechanism has ashielding layer, each interconnection path including the impedancecontrolled mechanism may not suffer from the crosstalk caused by the viahole on the backplane according to the conventional solution.

Furthermore, according to the present embodiment, the cable 54 is buriedin the front card 301/rear card 302. Therefore, the signal can betransmitted without passing through the via hole 312/322 on the frontcard 301/rear card 302 and the via 314/324, which further minimizes theinterference on the interconnection path. In addition, the cable 54 isprevented from being cut off by force due to being exposed to thesurface of the front card 301/rear card 302. Thus, the transmissionperformance and reliability of the interconnection path is furtherimproved.

In the backplane interconnection system according to the presentembodiment, each connection mechanism may also be replaced with theconnection mechanism in the other embodiments of the backplaneinterconnection system. It is to be noted that not all of the connectionmechanisms in the system need to take the form of such connectionmechanism.

FIG. 17 is an illustration of a coplanar processing for cables andcircuit board surface according to a sixth embodiment of the backplaneinterconnection system of the present invention. As illustrated in FIG.17, the cable 54 is buried in the front card 301/rear card 302 and thetwo ends of the cable 54 are kept in a same plane with the front card301/rear card 302. The process includes the following steps.

a. The cable 54 passes through the path or groove which is in the frontcard 301/rear card 302 and is manufactured in advance.

b. The coplanarity of the cable 54 penetrating the front card 301/rearcard 302 is assured by mechanical manufacturing.

In this step, in a direction parallel to the front card 301/rear card302, a metal cutting tool 70 with an angular velocity w and a feed rateV is used to cut the portion of the cable 54 which protrudes out of thesurface of the front card 301/rear card 302.

c. The surface is processed as desired. For instance, the surface may beprocessed by way of Immersion Silver, Immersion Tin, or goldelectroplate, etc.

The foregoing is a detailed description to the backplane interconnectionsystem and the method for mounting the backplane interconnection systemaccording to the present embodiment. A traditional connection methodsuch as surface mounted manner may be utilized where no special note ismade.

The foregoing embodiments all focus on an orthogonal backplaneinterconnection system as an example. If the backplane interconnectionsystem adopts the traditional mounting structure as illustrated in FIG.1, the technical solutions of the present embodiment can also beadopted. That is, an impedance controlled mechanism can be mounted onthe backplane and a backplane connector is then mounted on the backplaneand the corresponding pin is coupled to the impedance controlledmechanism. Consequently, the crosstalk due to the via hole on thebackplane can be eliminated.

Moreover, the transceiver on the slave circuit board can be coupled tothe backplane connector via the high-speed cable. As such, signalattenuation among each interconnection path can be eliminated and theloss on each interconnection path can be reduced.

In all the foregoing embodiments, the cable connector 55 is mounted soas to ensure the reliability of connection between the cable 54 andother part. Thus, the cable can be prevented from being cut off byexternal force and from breaking the original connection easily. In theforegoing embodiments, the cable connector 55 can be omitted. The cable54 can be welded directly to the other part.

As can be seen from each backplane interconnection system of the variousembodiments and the process for manufacturing backplane, backplaneconnector in the system,

the backplane is configured with a structure which has a shieldingfunction and an impedance controlled function to realize the function ofa via hole, i.e., replacing the via hole on the existing circuit board.Meanwhile, the problem of the inconsistency of the impedance and thecrosstalk among each interconnection path is solved. Thus, thetransmission performance of the circuit board is improved.

In the embodiment of the present invention, high-speed signal cable isused to transmit high-speed signal between each circuit board and theconnector. Compared with the traditional method of transmitting thesignal along a differential signal line on the circuit board, thepresent embodiment further succeeds in minimizing the loss on eachinterconnection path and the problem, that the delay varies in each pathin the pair of the differential path due to anisotropy of the materialused by traditional manufacturing for the printed slave circuit board,is overcome. Thus, the issue of reduced performance for theinterconnection path in the circuit board interconnection system isalleviated or overcome.

Moreover, the embodiments of the present invention provide differentimpedance controlled mechanisms depending on the actual applications.The embodiments utilize various connection mechanisms to realize theconnection between the high-speed cable and the transceiver and thecircuit board connector as well as the connection between the circuitboard connector and the impedance controlled mechanism. In addition, theimpedance controlled mechanism can also be applied to the slave circuitboard for substituting the existing via hole. Thus, these embodimentsallow the present invention to be applied to different practicalapplication environment and is capable of further improving thetransmission performance of the interconnection paths in the circuitboard interconnection system.

The technical solutions according to the foregoing embodiments may alsobe applicable to other circuit board interconnection system in additionto the backplane interconnection system.

For instance, the impedance controlled mechanism as illustrated in FIG.7 a, or 7 b, or 8 a, or 8 b can be mounted on the multi-layer circuitboard. The connector on which another functional circuit board ismounted on is mounted on the multi-layer circuit board and is coupled tothe impedance controlled mechanism on the multi-layer circuit board. Thefunctional circuit board mounted on the connector is coupled to a signalline on each layer of the multi-layer circuit board via the impedancecontrolled mechanism to allow the transmission of the signals.

Because the impedance value of the impedance controlled mechanism ineach interconnection path is set depending on the actual circuitenvironment, the impedance is stable and is not subject to interference.Thus, the impedance continuity for each interconnection path formed byeach layer of signal line connecting between the function circuit boardand the multi-layer circuit board via the impedance controlled mechanismis enhanced. Moreover, if the functional circuit board is coupled toeach layer of the multi-layer circuit board via multiple impedancecontrolled mechanism, respectively, each interconnection path includingthe impedance controlled mechanism may not suffer from the crosstalksince the impedance controlled mechanism has a shielding layer.

The foregoing is merely preferred embodiments of the present inventionand is not intended to be limiting to the scope of the presentinvention. Any modifications, equivalents, improvements made within thespirit and principle of the present invention shall be construed as fallwithin the scope of the present invention.

1. A circuit board interconnection system, characterized in comprising,a first circuit board, a second circuit board, a third circuit board, afirst connector and a second connector; wherein the first connector andthe second connector are mounted at two sides of the first circuitboard, respectively; the second circuit board is mounted on the firstconnector; the third circuit board is mounted on the second connector;the first connector and the second connector mounted respectively at thetwo sides of the first circuit board are coupled to each other via animpedance controlled mechanism on the first circuit board.
 2. The systemof claim 1, characterized in that, the impedance controlled mechanismcomprises a metallic conductor, a dielectric layer covering outersurface of the metallic conductor, and a metallized via hole on thefirst circuit board; wherein the metallic conductor covered with thedielectric layer is inserted in the metallized via hole on the firstcircuit board.
 3. The system of claim 1, characterized in that, theimpedance controlled mechanism comprises a metallized via hole on thefirst circuit board, a dielectric layer on inner wall of the metallizedvia hole, and conductive material covered by the dielectric layer or ametallized layer on inner surface of the dielectric layer.
 4. The systemof claim 2, characterized in that, the second circuit board isperpendicular to the third circuit board; the impedance controlledmechanisms on the first circuit board are arranged in diagonal symmetry.5. The system of claim 1, characterized in that, the first connectorand/or the second connector is coupled to the impedance controlledmechanism via a press-fitted pin mechanism.
 6. The system of claim 1,characterized in that, the first connector and/or the second connectoris coupled to a surface-mount signal pin surface-mounted on theimpedance controlled mechanism.
 7. The system of claim 1, characterizedin that, the first circuit board has a through hole at a position wherethe first connector and/or the second connector is mounted thereon; theimpedance controlled mechanism comprises a hollow penetrating pin whichcan be inserted into the through hole and a penetrating pin which can beinserted into the hollow penetrating pin; the hollow penetrating pin isin a hollow structure made from metal material and the inner wall of thehollow penetrating pin is provided with a dielectric layer; thepenetrating pin is a metallic conductor; the hollow penetrating pin islocated on the first connector at one side of the first circuit board;the penetrating pin is located on the second connector at the other sideof the first circuit board.
 8. The system of claim 7, characterized inthat, the inner surface of the dielectric layer of the hollowpenetrating pin is provided with a metallic conductor layer.
 9. Thesystem of claim 5, characterized in that, the system further comprisesat least two transceivers and a cable connecting the two transceivers;the two transceivers are mounted on the second circuit board and thethird circuit board, respectively.
 10. The system of claim 9,characterized in that, the system further comprises a cable connector;the transceiver and the first connector are located at one side of thesecond circuit board and the cable connector is located at the otherside of the second circuit board; two ends of the cable are coupled totwo cable connectors respectively; on the second circuit board, there isfurther provided with at least two via holes coupled to the transceiversor an impedance controlled mechanism coupled to the transceivers; eachcable connector is press-fitted into the via hole coupled to the secondcircuit board and the transceivers via a press-fit pin; or each cableconnector is surface-mounted on the impedance controlled mechanismcoupled to the second circuit board and the transceivers; the firstconnector is press-fitted by a press-fit pin into a same via hole inwhich the cable connector on the second circuit board is press-fitted;or the first connector is surface-mounted on a same impedance controlledmechanism on which the transceiver on the second circuit board issurface-mounted.
 11. The system of claim 9, characterized in that, thesystem further comprises cable connectors; wherein the transceivers, thefirst connector and the cable connectors are located at one side of thesecond circuit board; two ends of the cable are coupled to two cableconnectors respectively; the transceivers are in a surface-mountpackaging structure; the cable connector coupled to one end of the cableis coupled to a pad of a pin of the transceiver via a microstrip or thecable connector coupled to one end of the cable is surface-mounted onthe top of the transceiver and directly coupled to the pin of thetransceiver; the cable connector coupled to the other end of the cableis surface-mounted on the first connector.
 12. The system of claim 9,characterized in that, the cable is buried in the second circuit board;the transceiver and the first connector are surface-mounted at one sideof the second circuit board; one end of the cable coupled to thetransceiver by directly coupling to the bottom of the pad of the pin ofthe transceiver; the other end of the cable is coupled to a side of thesecond circuit board where the first connector is surface-mountedthereon.
 13. The system of claim 1, characterized in that, the firstcircuit board is a backplane.
 14. A circuit board interconnectionsystem, comprising a first circuit board, a connector mounted on thefirst circuit board, and a second circuit board coupled to the firstcircuit board via the connector; the system characterized in that, thefirst circuit board comprises an impedance controlled mechanism thereon,wherein the impedance controlled mechanism is electrically coupled tothe connector and the second circuit board is electrically coupled tothe first circuit board via the connector and the impedance controlledmechanism.
 15. The system of claim 14, characterized in that, the firstcircuit board comprises a signal layer, wherein the second circuit boardis coupled to the signal layer of the first circuit board via theconnector and the impedance controlled mechanism.
 16. The system ofclaim 14, characterized in that, the impedance controlled mechanismcomprises a metallic conductor, a dielectric layer covering the outersurface of the metallic conductor, and a metallized via hole on thefirst circuit board; wherein the metallic conductor covered with thedielectric layer is inserted in the metallized via hole on the firstcircuit board.
 17. The system of claim 14, characterized in that, theimpedance controlled mechanism comprises a metallized via hole on thefirst circuit board, a dielectric layer on the inner wall of themetallized via hole, and conductive material covered by the dielectriclayer or a metallized layer on the inner surface of the dielectriclayer.
 18. A circuit board, characterized in that, an impedancecontrolled mechanism is provided at a position where a connector ismounted the circuit board.
 19. The circuit board of claim 18,characterized in that, the impedance controlled mechanism comprises ametallic conductor, a dielectric layer covering the outer surface of themetallic conductor, and a metallized via hole on the circuit board;wherein the metallic conductor covered with the dielectric layer isinserted in the metallized via hole on the circuit board.
 20. Thecircuit board of claim 18, characterized in that, the impedancecontrolled mechanism comprises a metallized via hole on the circuitboard, a dielectric layer on the inner wall of the metallized via hole,and conductive material covered by the dielectric layer or a metallizedlayer on the inner surface of the dielectric layer.
 21. A connectorassembly, comprising a first connector and a second connector,characterized in that, the connector assembly comprises an impedancecontrolled mechanism, the impedance controlled mechanism comprises: ahollow penetrating pin provided on the first connector, wherein thehollow penetrating pin is in hollow structure made from metal materialand the inner wall of the hollow penetrating pin is provided with adielectric layer; a penetrating pin provided on the second connector,wherein the penetrating pin is a metallic conductor for inserting intothe hollow penetrating pin.
 22. The connector assembly of claim 18,characterized in that, the inner surface of the dielectric layer of thehollow penetrating pin is covered with a metallic conductor layer forcontacting the inserted penetrating pin.
 23. An impedance controlledmechanism, characterized in that, the impedance controlled mechanism isapplied to a circuit board, the impedance controlled mechanism comprisesa metallic conductor, a dielectric layer covering the outer surface ofthe metallic conductor, and a metal shielding layer covering the outersurface of the dielectric layer.
 24. A communication device, comprisinga circuit board interconnection system, the circuit boardinterconnection system is characterized in comprising a first circuitboard, a second circuit board, a third circuit board, a first connectorand a second connector; wherein the first connector and the secondconnector are mounted at two sides of the first circuit board,respectively; the second circuit board is mounted on the firstconnector; the third circuit board is mounted on the second connector;the first connector and the second connector mounted respectively at twosides of the first circuit board are coupled to each other via animpedance controlled mechanism on the first circuit board.
 25. Thecommunication device of claim 24, characterized in that, the impedancecontrolled mechanism comprises a metallic conductor, a dielectric layercovering the outer surface of the metallic conductor, and a metallizedvia hole on the first circuit board; wherein the metallic conductorcovered with the dielectric layer is inserted in the metallized via holeon the first circuit board.
 26. The communication device of claim 24,characterized in that, the impedance controlled mechanism comprises ametallized via hole on the first circuit board, a dielectric layer onthe inner wall of the metallized via hole, and conductive materialcovered by the dielectric layer or a metallized layer on the innersurface of the dielectric layer.
 27. A method for manufacturing acircuit board, characterized in comprising: mounting an impedancecontrolled mechanism on the circuit board, wherein the impedancecontrolled mechanism is configured to couple connectors mounted at twosides of the circuit board.
 28. The method of claim 27, characterized inthat, the mounting the impedance controlled mechanism comprises:manufacturing a metallized via hole on the circuit board; pressing ametallic conductor with dielectric into the metallized via hole;cutting, with a metal cutting tool, a portion of the impedancecontrolled mechanism which protrudes out of the surface of the circuitboard along a direction parallel to the surface of the circuit board.29. The method of claim 27, characterized in that, the mounting theimpedance controlled mechanism comprises: manufacturing a metallized viahole on the circuit board; injecting insulated material into themetallized via hole; manufacturing a non-metallized via hole in theinsulated material; injecting conductive material into thenon-metallized via hole or metalizing the non-metallized via hole byelectroplating.